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I just purchased a new AntiGravity Lithium Battery for my 2017 991.2. It’s a 40ah H6 size. I installed it today and all works well. Before installing I gave it an overnight full charge from my CTEK Lithium Charger. The batteries arrive with an adequate charge but I did the CTEK charge for good measure.
Downtime between batteries was about a minute. No setting lost except for the clock that did an auto reset in a few minutes once the new battery was installed. Only minor problem I faced was the battery hold down bracket at the lower right side edge that fastens into the battery support plate. I went from the mid size H7 to the small size H6 battery so it used the third bolt hole. It appeared the Porsche bolt holding it was slightly too short to engage the threaded hole. With some patience and extra effort it barely engaged the threads and allowed me to tighten it. It may be that the AntiGravity Battery bottom case lip is slightly thicker than the OEM’s lip. AntiGravity should provide a longer bolt with their battery. I was told by AntiGravity the battery switch is “plug and play’ so I didn’t reprogram the battery swap. Took a 12 mile drive with the AntiGravity Battery and the charging rate remained a steady 13.7 volts. The OEM AGM Porsche Battery with 20% life left would charge from 14.6 - 14.8 volts.
Just an FYI I foundWalmart Everstart H8 boat battery to have identical dimensions as my 991.2 Porsche 911 battery. H8 AGM at Walmart with 4 year full replacement warranty $149.
I just purchased a new AntiGravity Lithium Battery for my 2017 991.2. It’s a 40ah H6 size. I installed it today and all works well. Before installing I gave it an overnight full charge from my CTEK Lithium Charger. The batteries arrive with an adequate charge but I did the CTEK charge for good measure.
Downtime between batteries was about a minute. No setting lost except for the clock that did an auto reset in a few minutes once the new battery was installed. Only minor problem I faced was the battery hold down bracket at the lower right side edge that fastens into the battery support plate. I went from the mid size H7 to the small size H6 battery so it used the third bolt hole. It appeared the Porsche bolt holding it was slightly too short to engage the threaded hole. With some patience and extra effort it barely engaged the threads and allowed me to tighten it. It may be that the AntiGravity Battery bottom case lip is slightly thicker than the OEM’s lip. AntiGravity should provide a longer bolt with their battery. I was told by AntiGravity the battery switch is “plug and play’ so I didn’t reprogram the battery swap. Took a 12 mile drive with the AntiGravity Battery and the charging rate remained a steady 13.7 volts. The OEM AGM Porsche Battery with 20% life left would charge from 14.6 - 14.8 volts.
Problem with fastening this bracket
HI Straka, we have never heard of the bolt not being long enough on the "cleat" that holds down the battery. Our footer on the battery is the exact same as the Porsche batteries so it should not hold the cleat in a raised position that would require a longer bolt. You may want to see if you can push the battery the the Left (passenger side), and to the back a little more on the installation because the porsche battery tray has lips that the footer on the battery needs to slide into/under. It might not be sliding quite enough under the "lip" of the battery tray so that your cleat is laying as flat as it should perhaps. Anyway just wanted to suggest that since we have never heard of this happening to date.
Just an FYI I found Walmart Everstart H8 boat battery to have identical dimensions as my 991.2 Porsche 911 battery. H8 AGM at Walmart with 4 year full replacement warranty $149.
That sounds like a great deal as long as it is an AGM and not a GEL battery typically used with trolling motors. A GEL battery would end up being overcharged with our 991 charging system.
I get 14+ years out of my "standard FLA" batteries, so if I am paying twice to three times as much for a battery, I would expect a 28 or 42 year battery life and that is not going to happen.
No its AGM I use Walmart car batteries in my boat not marine batteries. I use my boat much more like a car. No trolling motor, no water pumps, just start and run engine.
as an aside: i just had to jump my 991 after a bunch of time away this summer and fall. i had done it before in my 997 so i thought i knew the procedure - but sat there for 20 minutes scratching my head as to why the fuse panel 12v post wasn't working. tried the 12v override on my jumper unit, tried the 12v supply mode on my charger, and i tested each with multimeter. i thought my car had bricked itself.
turns out there's some kind of (anti-corrosion?) coating on the damn door hinge. i had to wiggle the crap out of it to get it to contact. worked fine after that. if there's a better spot to do this, let me know.
also remember to use the fob to open the frunk if the rocker panel pull switch doesn't work!
Last edited by chiffonade; 12-11-2022 at 08:52 PM.
Bought the battery with the 15% Black Friday Discount from retail price for their 40ah H6 size. At that time a free portable jump start was included. Shipping is free.Using it now for over a week. Quickly cranks motor over. May charge up to 14.2 V after start up for a few miles and then establishes the charging rate at 13.7 V. I'm happy with the purchase.
I haven't had to replace my battery, yet, but have replaced in dozens of other vehicles over the years - I did use AGM batteries in the jet skis, but all others have been one manufacturer of FLA batteries - all seem to work well, and most for a long time.
$740 seems a bit steep ... isn't that 3-4X the cost of a FLA battery? Are there advantages to this approach? (I don't think vehicle weight or CG or balanceis one of them, btw, except they are easier to lift over the frunk area :-)
I haven't had to replace my battery, yet, but have replaced in dozens of other vehicles over the years - I did use AGM batteries in the jet skis, but all others have been one manufacturer of FLA batteries - all seem to work well, and most for a long time.
$740 seems a bit steep ... isn't that 3-4X the cost of a FLA battery? Are there advantages to this approach? (I don't think vehicle weight or CG or balanceis one of them, btw, except they are easier to lift over the frunk area :-)
12-06-2022, 10:49 AM
